saving progress

Author: lrvideckis

library/data_structures/README.md

@@ -0,0 +1,41 @@
+#pragma once
+//! @code
+//!   binary_trie bt;
+//!   bt.update(num, 1); // insert
+//!   bt.update(num, -1); // erase
+//! @endco
+//! @time O(q * mx_bit)
+//! @space O(q * mx_bit)
+const ll mx_bit = 1LL << 60;
+struct binary_trie {
+  struct node {
+    int siz = 0;
+    array<int, 2> next = {-1, -1};
+  };
+  deque<node> t;
+  binary_trie(): t(1){}
+  void update(ll num, int delta) {
+    int v = 0;
+    for (ll bit = mx_bit; bit; bit /= 2) {
+      bool b = num & bit;
+      if (t[v].next[b] == -1) {
+        t[v].next[b] = sz(t);
+        t.emplace_back();
+      }
+      v = t[v].next[b];
+      t[v].siz += delta;
+    }
+  }
+  ll walk(ll num) {
+    int v = 0;
+    ll res = 0;
+    for (ll bit = mx_bit; bit; bit /= 2) {
+      bool b = num & bit;
+      int u = t[v].next[b];
+      if (u != -1 && t[u].siz > 0)
+        v = u, res |= num & bit;
+      else v = t[v].next[!b], res |= (~num) & bit;
+    }
+    return res;
+  }
+};

library/data_structures/binary_trie.hpp

@@ -5,7 +5,6 @@
 struct BIT {
   vector<ll> s;
   BIT(int n): s(n) {}
-#include "bit_uncommon/vector_constructor.hpp"
   void update(int i, ll d) {
     for (; i < sz(s); i |= i + 1) s[i] += d;
   }
@@ -17,5 +16,5 @@ struct BIT {
   ll query(int l, int r) { // [l, r)
     return query(r) - query(l);
   }
-#include "bit_uncommon/walk.hpp"
+#include "bit_extra_members/walk.hpp"
 };

library/data_structures/binary_trie/binary_trie.hpp

@@ -0,0 +1,10 @@
+//! Requires s[i] >= 0
+//! max r such that sum of [0,r) < sum, or -1
+int walk(ll sum) {
+  if (sum <= 0) return -1;
+  int r = 0;
+  for (int pw = bit_floor(size(s)); pw; pw >>= 1)
+    if (r + pw <= sz(s) && s[r + pw - 1] < sum)
+      sum -= s[(r += pw) - 1];
+  return r;
+}